db: Detect deleted Tracks during Library scanning

And use the tagger.untag_track() function to clean up and remove them
from the database.

Signed-off-by: Anna Schumaker <Anna@NoWheyCreamery.com>

emmental/db/libraries.py

@@ -28,6 +28,13 @@ class Library(playlist.Playlist):
         super().__init__(queue=idle.Queue(), **kwargs)
         self.scan()
 
+    def __check_trackid(self, trackid: int) -> bool:
+        track = self.table.sql.tracks.rows.get(trackid)
+        if track is not None and not track.path.exists():
+            tagger.untag_track(self.table.sql, track)
+            track.delete()
+        return True
+
     def __queue_delete(self) -> bool:
         self.table.delete(self)
         return True
@@ -55,6 +62,9 @@ class Library(playlist.Playlist):
         self.readdir = path.readdir_async(self.path)
         if self.readdir is not None:
             self.online = True
+            self.load_tracks()
+            self.queue.push_many(self.__check_trackid,
+                                 [(tid,) for tid in self.tracks.trackids])
             self.queue.push(self.__queue_tracks)
             self.tagger = tagger.Thread()
         return True

tests/db/test_libraries.py

@@ -75,6 +75,8 @@ class TestLibraryObject(tests.util.TestCase):
         """Test scanning an online Library path."""
         self.assertEqual(self.library.queue[0],
                          (self.library._Library__scan_library,))
+        self.library.tracks.trackids = {1, 2, 3}
+        self.library.load_tracks = unittest.mock.Mock()
 
         with unittest.mock.patch.object(self.library.queue,
                                         "push") as mock_push:
@@ -83,6 +85,7 @@ class TestLibraryObject(tests.util.TestCase):
 
         mock_is_dir.return_value = True
         self.assertTrue(self.library.queue.run_task())
+        self.library.load_tracks.assert_called()
 
         mock_is_dir.assert_called()
         self.assertTrue(self.library.online)
@@ -91,8 +94,11 @@ class TestLibraryObject(tests.util.TestCase):
                               emmental.path.ReaddirThread)
         self.assertIsInstance(self.library.tagger,
                               emmental.db.tagger.Thread)
-        self.assertEqual(self.library.queue[0],
-                         (self.library._Library__queue_tracks,))
+        self.assertEqual(self.library.queue._tasks,
+                         [(self.library._Library__check_trackid, 1),
+                          (self.library._Library__check_trackid, 2),
+                          (self.library._Library__check_trackid, 3),
+                          (self.library._Library__queue_tracks,)])
 
     def test_scan_offline(self):
         """Test scanning an offline Library path."""
@@ -166,6 +172,27 @@ class TestLibraryObject(tests.util.TestCase):
         tagger.tag_file.assert_not_called()
         tagger.get_result.assert_called_with(self.sql, self.library)
 
+    @unittest.mock.patch("emmental.db.tagger.untag_track")
+    def test_scan_check_trackid(self, mock_untag: unittest.mock.Mock()):
+        """Test that deleted Tracks are removed during scanning."""
+        track = unittest.mock.Mock()
+        track.path = pathlib.Path("/a/b/c/1.ogg")
+
+        self.library._Library__check_trackid(1)
+        mock_untag.assert_not_called()
+
+        self.sql.tracks.rows[1] = track
+        with unittest.mock.patch.object(type(track.path),
+                                        "exists") as mock_exists:
+            mock_exists.return_value = True
+            self.library._Library__check_trackid(1)
+            mock_untag.assert_not_called()
+            track.delete.assert_not_called()
+
+        self.library._Library__check_trackid(1)
+        mock_untag.assert_called_with(self.sql, track)
+        track.delete.assert_called()
+
     def test_stop(self):
         """Test stopping a Library's background work."""
         readdir = unittest.mock.Mock()